Researchers Study Factors That May Complicate Concussion Recovery

Recognition and diagnosis of concussions have exploded over the past decade, mainly due to increased media attention on how professional sports teams deal with these serious injuries. Nearly 173,000 children and adolescents are seen in emergency departments annually for sports- and recreation-related traumatic brain injuries (TBI), including concussions, according to the Centers for Disease Control and Prevention.

“Concussions have become a hot button issue across the country,” said Daniel J. Corwin, MD, of the Division of Emergency Medicine at CHOP. “We have become much more aware and adept at concussion diagnosis and management.”

As the number of children treated for concussions continues to increase, the evidence-based program Minds Matter developed by concussion experts at The Children’s Hospital of Philadelphia has expanded to clinicians in the emergency room and primary care practices. A concussion is a mild TBI caused by a blow or jolt to the head or body that causes the brain to shake. The injury disrupts how well the brain’s cells function and work together, and it can cause multiple symptoms, including headaches and dizziness, sleep problems, confusion, and irritability. Some symptoms are obvious and immediate, while others are more subtle and may not show up for several days.

A subset of patients may experience a more complicated recovery that can last for months. In a retrospective study published in the December issue of the Journal of Pediatrics, Dr. Corwin and colleagues investigated a broad group of characteristics that may help clinicians to identify which patients are most at risk for prolonged recovery.

“We suspect that there is something about these children that may predispose them to having poorer outcomes from concussion and longer recovery times,” Dr. Corwin said. “It is possible that even if a child has mild symptoms, they may have a longer recovery time if they have one of the pre-existing conditions or the specific types of clinical presentations that we studied.”

The study team hypothesized that patients with pre-existing mood disturbances or learning disabilities, dizziness as an initial symptom, abnormal findings upon vestibular examination, a history of prior concussion, and younger age would be associated with a more complicated recovery from concussions. They analyzed data collected via an electronic medical record query from patients aged 5 to 18 with concussion who were referred to CHOP’s sports medicine clinic.

The investigators examined several recovery outcomes, including how long on average it took for patients to be symptom-free (64 days), how long until they were fully cleared to return to learning without any academic accommodations (35 days), and how long until they were fully cleared for all activities, including sports (76 days). Overall, the study reported recovery times that were longer than the healing times estimated in previous studies among the general pediatric population (14 to 28 days).

Because it was a retrospective study, many of the differences that the researchers identified in association with specific patient characteristics did not reach statistical significance, but their findings could spark more in-depth studies of these predisposing factors. For example, the investigators found that patients with a history of anxiety and depression had prolonged recovery time and worse school outcomes.

“They may have underlying abnormalities that make their brain a little more sensitive to a given impact,” Dr. Corwin suggested as a hypothesis for future exploration.

He also anticipates that the study’s findings will prompt more research into how assessment of vestibular deficits could be incorporated into concussion exams to help with prognosis, which already is the standard for care for CHOP’s sports medicine specialists but is not done universally. The vestibular system includes parts of the inner ear and brain that help control balance and eye movements.

One element of the assessment tests near-point convergence, which determines how difficult it is for patients to see an object clearly as it moves closer. In the current study, patients who demonstrated abnormal near-point convergence ended up having prolonged symptoms and poorer school outcomes.

“Usually, an object becomes blurry at about 6 cm,” Dr. Corwin said. “We found that for some patients, an object was blurry at 10 cm to 20 cm, which can make schoolwork quite difficult.”

The study team also considered concussion patients who had difficulty looking horizontally and vertically back and forth rapidly, as they do in a classroom when taking notes. Patients with initial oculomotor abnormalities on physical examination also had prolonged symptoms and poorer school performance.

“Perhaps if these vestibular deficits are present at the initial exam, they could be markers that a concussion injury may cause more severe dysfunction,” Dr. Corwin said, adding that this is an area where researchers could help to provide future data.

Other factors that the study team associated with patients who took longer for their symptoms to resolve included those who reported dizziness or loss of consciousness at the time of injury, at least two prior concussions, and younger age, especially those 12 and under.

Future research also is needed to see how clinicians’ recommendations for physical rest and early cognitive rest — which restricts patients’ exposure to activities that may stress the brain and worsen symptoms, such as sports, schoolwork, computers, texting, or video games — could affect patient outcomes in these high risk groups.

“It can often be challenging to have patients cognitively rest,” Dr. Corwin said. “As clinicians are counseling families and following up with these patients, they can be aware of which children are at increased risk for prolonged recovery and worse outcomes, and hopefully better prepare them and set expectations from the beginning that will encourage them to rest more effectively.”